class_docstr: >>> Backbone()  # doctest: +ELLIPSIS +NORMALIZE_WHITESPACE
  Backbone(
    (l1): Linear(...)
    (l2): Linear(...)
  )
code: def forward(self, x):
      x = x.view(x.size(0), -1)
      x = torch.relu(self.l1(x))
      return torch.relu(self.l2(x))
  
imports: from os import path
  from typing import Optional
  import torch
  from lightning.pytorch import LightningDataModule, LightningModule, cli_lightning_logo
  from lightning.pytorch.cli import LightningCLI
  from lightning.pytorch.demos.mnist_datamodule import MNIST
  from lightning.pytorch.utilities.imports import _TORCHVISION_AVAILABLE
  from torch.nn import functional
  from torch.utils.data import DataLoader, random_split
label_desc: Use image node_id 2 for calling the Backbone obj's underlying member method code with example usage: obj.forward(x) and returns: torch